1. Field
The present disclosure relates generally to aircraft and more particularly to aeronautical information systems for use in operating aircraft. Still more particularly, the present disclosure relates to a moving map system for depicting minimum altitudes used in the operation of aircraft.
2. Background
Aeronautical charts depict many types of minimum altitudes to fly that indicate adequate vertical clearance from nearby terrain and manmade obstacles. Examples of minimum altitudes on charts are Minimum Off Route Altitudes (MORAs), Terminal Arrival Areas (TAAs) and Minimum Safe Altitudes (MSAs). While this application provides illustrative examples of Minimum Safe Altitudes (MSAs), the systems and methods described can be applied to many types of minimum altitudes depicted on dynamically generated charts.
A Minimum Safe Altitude (MSA) depiction typically includes a radius around a navigation aid on a map or chart. For example, Minimum Safe Altitude can be depicted as a twenty-five nautical mile circle around a navigation aid, where the navigation aid is used to indicate an airport on a chart or map. Minimum Safe Altitudes (MSAs) may include Minimum Reception Altitudes and Minimum Obstacle Clearance Altitudes, for example.
A Minimum Safe Altitude (MSA) radius typically includes one or more altitudes corresponding to a portion of the radius. For example, a radius might be sub-divided into sections defined by radials, with each radial having a corresponding altitude that an aircraft should keep as a minimum to clear terrain or obstacles in that section of the radius.
Charts and maps depicting areas around an airport usually contain large amounts of information. As a result, this area of the charts and map tends to be cluttered with graphical elements. A Minimum Safe Altitude (MSA) radius is often depicted as a separate black and white element in a different region of the chart apart from the geographical map depiction on paper charts. In some electronic charts, a Minimum Safe Altitude (MSA) radius is depicted as a static graphic overlay of the geographical map.
Therefore, it is advantageous to have a method and apparatus that takes into account one or more of the issues discussed above, as well as possibly other issues.